#include <stdio.h>
#include "vectors.h"
#include "gravity.h"

vector& gravity(vector& r,vector& v)
{
        int GMm=5000;
        return (-GMm/r.triple())*r;
}
vector& gravity(vector& r,vector& v,vector& dr)
{
        int GMm=5000;
        return (-GMm/(r-dr).triple())*(r-dr);
}

